1. Field of the Invention
The present invention relates to a power supply.
2. Description of the Related Art
In recent years, various kinds of electronic devices such as PDAs (Personal Digital Assistants), laptop personal computers, etc., include a great number of electronic circuits mounted thereon. Examples of such electronic circuits include: a CPU (Central Processing Unit) and a DSP (Digital Signal Processor) each of which performs digital signal processing; a liquid crystal panel; and other analog circuits and digital circuits. In a battery-driven electronic device which includes a battery as a power supply, each electronic circuit included therein operates using the battery voltage generated by the battery.